1 /*-------------------------------------------------------------------------
2 *
3 * dsm_impl.h
4 * low-level dynamic shared memory primitives
5 *
6 * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 * src/include/storage/dsm_impl.h
10 *
11 *-------------------------------------------------------------------------
12 */
13 #ifndef DSM_IMPL_H
14 #define DSM_IMPL_H
15
16 /* Dynamic shared memory implementations. */
17 #define DSM_IMPL_POSIX 1
18 #define DSM_IMPL_SYSV 2
19 #define DSM_IMPL_WINDOWS 3
SaPrintPolicyProtocol(IN SA_POLICY_PROTOCOL * SaPolicy)20 #define DSM_IMPL_MMAP 4
21
22 /*
23 * Determine which dynamic shared memory implementations will be supported
24 * on this platform, and which one will be the default.
25 */
26 #ifdef WIN32
27 #define USE_DSM_WINDOWS
28 #define DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE DSM_IMPL_WINDOWS
29 #else
30 #ifdef HAVE_SHM_OPEN
31 #define USE_DSM_POSIX
32 #define DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE DSM_IMPL_POSIX
33 #endif
34 #define USE_DSM_SYSV
35 #ifndef DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE
36 #define DEFAULT_DYNAMIC_SHARED_MEMORY_TYPE DSM_IMPL_SYSV
37 #endif
38 #define USE_DSM_MMAP
39 #endif
40
41 /* GUC. */
42 extern int dynamic_shared_memory_type;
43
44 /*
45 * Directory for on-disk state.
46 *
47 * This is used by all implementations for crash recovery and by the mmap
48 * implementation for storage.
49 */
50 #define PG_DYNSHMEM_DIR "pg_dynshmem"
51 #define PG_DYNSHMEM_MMAP_FILE_PREFIX "mmap."
LoadIgdDxeDefault(IN VOID * ConfigBlockPointer)52
53 /* A "name" for a dynamic shared memory segment. */
54 typedef uint32 dsm_handle;
55
56 /* All the shared-memory operations we know about. */
57 typedef enum
58 {
59 DSM_OP_CREATE,
60 DSM_OP_ATTACH,
61 DSM_OP_DETACH,
62 DSM_OP_DESTROY
63 } dsm_op;
64
65 /* Create, attach to, detach from, resize, or destroy a segment. */
66 extern bool dsm_impl_op(dsm_op op, dsm_handle handle, Size request_size,
67 void **impl_private, void **mapped_address, Size *mapped_size,
68 int elevel);
69
70 /* Implementation-dependent actions required to keep segment until shutdown. */
71 extern void dsm_impl_pin_segment(dsm_handle handle, void *impl_private,
72 void **impl_private_pm_handle);
73 extern void dsm_impl_unpin_segment(dsm_handle handle, void **impl_private);
74
75 #endif /* DSM_IMPL_H */
76